Aminobenzoquinones and aminonaphthoquinones as additives for imparting oxidative stability to organic compositions

ABSTRACT

The invention provides new aminobenzoquinones and aminonaphthoquinones, and the substituted members thereof, which are useful as antioxidant additives to organic compounds, especially lubricants.

United States Patent Braid et a1.

[54] AMINOBENZOQUINONES AND AMINONAPHTHOQUINONES AS ADDITIVES FOR IMPARTING OXIDATIVE STABILITY TO ORGANIC COMPOSITIONS [72] Inventors: Milton Braid, Westmont; Derek A.

Law, Pitman, both of NJ.

[52] U.S. Cl......260/396 R, 260/239 EQ, 260/283 R, 260/287 R, 260/288 R, 260/293.87, 260/293.88, 260/293.9, 260/326.85

[151 3,682,980 [4 1 Aug. 8, 1972 [51] Int. Cl ..C07c 97/08 [58] Field of Search ..260/396 R [56] References Cited UNITED STATES PATENTS 3,114,755 12/1963 Covey ..260/396 Primary Examiner-Lorraine A. Weinberger Assistant Examiner-L. Arnold Thaxton Attorney-Oswald G. Hayes, Andrew L. Gaboriault, Raymond W. Barclay and Claude E. Setliff ABSTRACT The invention provides new aminobenzoquinones and aminonaphthoquinones, and the substituted members thereof, which are useful as antioxidant additives to organic compounds, especially lubricants.

14 Claims, No Drawings CROSS REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of application Ser. No. 590,482, filed Oct. 31, 1966, now U.S. Pat. No. 3,445,391.

This invention relates to a new group of aminoquinones useful as additives to improve the oxidation stability of certain organic materials, especially lubricating oils.

Many industrial organic media are used under circumstances which contribute to their breakdown during service. Such media include lubricants and greases,

hydraulic fluids for brake and transmission systems, resins and plastics for coatings and structural articles. The severe operating conditions of modern engines, for example, including automotive and gas turbine engines, have often caused lubricating oils to deteriorate rapidly during use. This oxidation deterioration is accelerated by the use of higher engine operating temperatures than formerly used. Oxidative deterioration of the oil is usually accompanied by the formation of gummy deposits, sludge, acids, which may be strong enough to cause metal corrosion and other products of chemical breakdown. These products may seriously interfere with the lubrication operation. The increase in viscosity which results from the oxidation of lubricants impairs the proper function of engine components and depreciates engine performance and useful life.

Organic media are generally blended with additives, termed antioxidants which protect against oxidation. Although many of the older known additives have been found to be adequate in stabilizing some modern mineral oil lubricants and synthetic lubricant blends discovery of new and more effective additives would be highly desirable for improved protection in current engines and extension of operating limits for future engines.

It is one object of this invention to provide novel organic compositions which have improved oxidation stability. It is a'further object of this invention to provide novel compositions which afford protection against oxidation deterioration for organic media to which they have been added. Another object is to provide imwherein Q is benzoquinone, naphthoquinone or R" substituted derivatives thereof and R and R may each be'hydrogen, hydrocarbyl or substituted hydrocarbyl. At least one of R and R' is always a hydrocarbyl or substituted hydrocarbyl group. The term hydrocarbyl for the purpose of this invention, includes such organic groups as alkyl, alkenyl, cycloalkyl, aralkyl, alkaryl and substituted derivatives thereof, including groups containingoxygen, sulfur, nitrogen and halogen atoms, such as alkylaminoalkyl, hydroxyalkyl, alkoxyalkyl alkoxyaryl, alkoxyalkaryl, acyloxy and haloalkyl; or aryl, alkaryl and substituted derivatives thereof containing oxygen, sulfur, nitrogen and halogen groups; and n is l to 2. Each R and R group may be the same as another or several other R or R groups, or different therefrom. Also, the two groups attached to each nitrogen atom may be bonded in a cyclic structure to produce heterocyclic amino groups attached to the nucleus of the quinone. Thus R and R groups may be part of aziridyl, azetidyl, pyrrolidyl, tetrahydroquinolyl, and piperidyl radicals. The number of aliphatic carbon atoms for the org'ano groups, either individually or as representing a heterocyclic radical, may range from one to about 40 carbon atoms, and preferably from four to 20 carbon atoms per group. I

The aminoquinones of this invention preferably have the following specific structures wherein the R and R groups have the above mentioned definitions, and R" may occupy up to all of the available positions on the nucleus and has the same definition as Rand R or may also be halogen, hydroxy, alkoxy,

proved lubricating oil compositions capable of withstanding the oxidizing conditions of modern engines. These and other objects will become apparent from the following disclosure.

[t has now been discovered that organic compositions ordinarily susceptible to deterioration caused by oxidation may have improved stability by the addition thereto of a minor amount of a quinone having at least one amino group attached thereto. Suitable quinones include amino-substituted benzoquinones, naphthoqixinones, and organo-substituted derivatives thereof.

The aminoquinones of this invention have the general structure acyloxy, acylamido, carbalkoxy or substituted derivatives of these. The preferred substituents are those organo or substituted organo groups, and especially alkyl or substituted alkyl, having from one to about 40 carbon atoms.

Although the'alkyl groups on each nitrogen atom may be different, symmetrical alkyl amines are employed herein to illustrate the essential features of this invention.

The aminoquinones used in this invention may be prepared. by the reaction between a quinone and a primary or secondary amine; or by the reaction between the amine reactant and a hydroquinone. In the latter reaction, the reactants are dissolved in a suitable solvent and a stream of air or oxygen or other oxygen-containing gas is dispersed therethrough with agitation at or above room temperature. Alternatively, the oxidation step may be performed with an oxidizing agent, such as hydrogen peroxide, potassium permanganate,

manganese dioxide, sodium chlorate and the like. The mole ratio of the reactants may be varied to produce the desired product. Approximately a 05:1 to 1:1 ratio of amine to quinone may usually be used to produce monoaminobenzoquinones and naphthoquinones; a 2:1 to :1 ratio for the diaminobenzoquinone. It is preferred to have an excess of amine present in the reaction mixture.

As indicated above, the amine reactant may be a simple alkyl, cycloalkyl, or aralkyl amine, having from one to about 40 carbon atoms. Representative of these amines are ethylamine, butylamine, t-butylamine, t-octylamine, t-eicosylamine, n-hexylamine, n-octylamine, n-dodecylamine, n-octadecylamine, cyclohexylamine, benzylamine and the like. The substituted hydrocarbyl amines include hydroxyethylamine, 1,1-dimethyl-2- hydroxyethylamine, 1, l -dihydroxymethylethylamine, ethylenediamine, diethylaminoethylamine, and diethylaminopropylamine. Secondary and heterocyclic amines contemplated in this invention include dibutylamine, dihexylamine, di-2ethylhexylamine, piperidine and the like. If desired, two different amine reactants may be employed.

Monoaminoquinones found suitable in this invention include 2-propylamino-p-benzoquinone, 2-dibutylamino-p-benzoquinone, 2-t-butylaminonaphthoquinone, 2-amylamino-p-benzoquinone, 2-(1,1,3,3-tetramethyl)butylaminonaphthoquinon e, and other N-alkyl and di-N-alkyl derivatives. Also included are further substituted monoaminoquinones, such as 2-(2-diethylaminoethylamino)-p-benzoquinone, 2-(3-diethylaminopropylamino)naphthoquinone, and 2-(1,1-dimethyl-2-hydroxyethylamino)naphthoquinone; and those having nucleus-substituted groups, such as 2-t-butyl-5-butylamino-p-benzoquinone and Z-t-butyl-S- benzylamino-p-benzoquinone.

The bisaminoquinones produced in accordance with this invention include 2,5- and 3,5-bisamino-pbenzoquinones, such as 2,5-bis-butylamino-pbenzoquinone, 2,5-bis-n-hexylamino-p-benzoquinone, 2,5-bis-(1,l,3,3-tetramethylbutylamino)-p-benzoquinone, 2,5-bis-t-octy1amino-p-benzoquinone, 2,5-bis-tnonylamino-p-benzoquinone, 2,5-bis-n-dodecylaminop-benzoquinone, 2,5-bis-piperidinyl-p-benzoquinone and 2,5-bis-cyclohexylamino-p-benzoquinone.

Aminoquinones with functional group substituents may be further reacted to improve solubility or antioxidant effectiveness or compatibility with other components of lubricant formulations. Representative of these further reactions are alkylation or acylation of amino or hydroxy substituent groups. Such products as 2,5-bis-( 1 l -dimethyl-2-ethoxyethylamino)-pbenzoquinone, 2,5-bis-(1,1-dimethyl-2-caproxyethylamino )-p-benzoquinone, 2,5-bis-( 1,1-dicaproxymethylethylamino)-p-benzoquinone, 2,5-bis-( 1 ,1-

climethyl-2-acetoxyethylamino)-p-benzoquinone, 2,5-

bis-(1,1-dimethyl-2-caproyloxyethylamino)-pbenzoquinone, 2,5-bis-( 1,1-diacetoxymethylethylamino-p-benzoquinone, and 2,5-bis-(l,1- dicaproyloxymethylethylamino)-p-benzoquinone are representative of the products of such reactions.

We have found that, in accordance with this invention, the presence of these amfnoquinones aid in preventing the breakdown of industrial organic substances normally susceptible to oxidation deterioration when subjected to oxidation and other deteriorative forces, particularly at high temperatures. These additives have been found to reduce, in an unexpectedly improved manner, the formation of acids and the viscosity change in lubricating compositions during use. Such media as plastics and rubbers, including polyglycol ethers, polyurethanes, polyvinyl compounds, conjugated diene polymers (as GR-S rubbers), and the like, may be improved by the aminoquinones of this invention. The organic substances of primary interest in this invention are lubricating oil compositions in which the base medium is a hydrocarbon mineral oil or one of the synthetic lubricating fluids, the latter being suitable for use in gas turbine engines, such as jet aircraft engines. Such synthetic fluids include polyolefin fluids, polyalkylene oxide fluids, silicone polymer fluids, polyarylether fluids, polyacetals, and organic ester fluids. This latter class includes polyesters, diesters, such as those prepared from dicarboxylic acids and monohydric alcohols or glycols and monocarboxylic acids, triesters including, for example, esters prepared from dimethylolpropane and monocarboxylic acids, and tetraesters prepared from pentaerythritol and monocarboxylic acids, the acids in these ester fluids having from about 1 to about 30 carbon atoms. Special attention is given in this invention to the tetraester fluids of pentaerythritol and monocarboxylic acids. Solid lubricants capable of being compounded may also be employed as the base media in this invention.

The following illustrative examples are intended to describe the invention more fully and are not deemed a limitation of the scope thereof. All parts and percentages are by weight unless otherwise specified.

EXAMPLE 1 In a suitable reactor, grams (1.5 moles) of hydroquinone was dissolved in 1 liter of methanol, and 230 grams (3.15 moles) of n-butylamine was added at 25 C. as the mixture was stirred. The temperature rose to 40 C. during which a color change was observed. After 5 minutes of stirring, a slow stream of oxygen was passed through the mixture. The temperature rose to 51 C. over a 2-hour period. A red crystalline product, 2,5-bis-n-butylamino-p-benzoquinone, commenced to precipitate. The total oxygen treatment lasted for 16 hours. Afterward, the solid was filtered off and washed in methanol, yielding 237 grams (63 percent) of product; m.p. 157-l 58 C.

Anal: Calc'd: %C, 67.17; %H, 8.86; %N, 11.19

Found: %C, 67.34; %H, 8.48; %N, l 1.30

EXAMPLE 2 In a suitable reactor were added 108 grams (1 mole) of benzoquinone and 292 grams (4 moles) of t-butylamine in a benzene solution. The mixture was held at a temperature in the range of 45 to 65 C. for three hours. At the end of this time, the mixture was filtered and unreacted amine and solvent were removed. A total of 93 grams (73 percent yield) of product, 2,5-bist-butylamino-p-benzoquinone, was obtained; m.p. 239240 C.

Anal: Calcd: %C, 67.17; %H, 8.86;%N, 11.19

Found %C, 66.93; %H, 8.90; %N, 11.30

5 6 EXAMPLE 3 T B 1 Following the method of Example 1, n-octylamine was reacted with hydroquinone. The oxidation was carq, ried out for a period of 24 hours. A yield of 63 percent I 5 Addlllve N.N. of lead of crude 2,5-b1s-n-octylamino-p-benzoqumone, m.p. com Kv loss 134C.,W3.S obtained. wt.% crease 100F. sludge mg.

Anal: Calcd: %C, 72.87; %H, 10.56; %N, 7.73 ;:'S 5 9 390 Found: %C, 73.08; %H, 10.35; %N, 7.71 i i 38 415 i 5 1 2,5-Bis-t-butylamino-p- EXAMPLE4 benzoquinone l 0.79 8 trace 6.3 2,5-Bis-n-hexylamino-p- Following the method of Example 1, cyclohexg g z 1 L0 5 heavy IS-IIOC am O- ylamme was reacted w1th hydroqumone. The ox1dat1on benzoquinonz m p l L7 16 n 72 was carried out for a perlod of 19 hours. A yield of 34 .5-Bi -d decylaminopercent of crude 2,5-bis-cyclohexylamino-pl5 ggz' zfi'ggf l3 A? a: z benzoquinone, m.p. 208 C., was obtained. 2,5-Bis-piperidinyl-p- Anal: Calcd: %C, 71.48; %H, 8.67; %N, 9.25 benlqquinone 2 I06 heavy L0 F d 7' c 71 1s- 7 H s 64- 7 N 966 oun o 0 1 0 amino-p-benzoquinone 0.75 4.84 404 nil 6.0

EXAMPLES Sto 13 20 6 EXAMPLES 14 to 21 Usmg procedures s1m1lar to Example 1, a number of I amines were reacted with hydroquinone to produce the Using procedures similar to Example 2, a number of corresponding 2,5-diorganoamino-p-benzoquinone. amines were reacted with benzoquinone to produce the Procedural conditions and results are tabulated in corresponding 2,5-diorganoamino-p-benzoquinone. Table l. 25 Results are tabulated in Table lll.

TABLE 1 Oxidation Crude C H N time, Yield, product Example No. Amine reactant hrs percent P., 0 Found Calcd Found Calc'd Found Calcd 65 41 212 60. 90 61. 85 6. s9 7. 27 14. 3o 14'. 42 64 53 19a 64. 92 66. 05 6. 21 6. 47 12. 6 12. a4 64 68 196 67. 67.17 8. 96 8.86 11.1 11.19 20 25 85 7s. 46 7s. 04 11.80 12. 23 4. 4 4. 35 6 70 247 62. 39 63. 10 6. 79 6. 24 12. 4 12.38 22 6 .663 6-21 1. 2 66 61 6. 13 88 176 9. 96 10.21 1 E3 alkanes ranging from 013 to C16 (commercially, Armeen L-ll").

1 24 hrs. air. I fi ee i m EVALUATION OF PRODUCTS TABLE lll The quinones of this invention were tested in a cata- C d Carbon Hydrogen Nitrogen lytic oxidation test for lubricants, using as the base g s medium a synthetic ester lubricant. This lubricant is Ex. reactant melting p p y the esterification of technical grade p no.am1ne 581m, calcdfound calc d found calcd found taerythritol with a mixture of commercial valeric and pelargonic acids. The test lubricant composition is sub- 14 1,1,11,3- ected to a stream of an whrch 1s bubbled through the Temm 1 composition at a rate of 5 liters per hour at 425 F. for ethylbu- :24 hours. Present in the composition are metals com- 15 "39440 72431056 1033 monly used as materials of engine construction, namelamina 73,80 72m 1034 1646 717 645 l6 t-Eicosylamine a. 15.6 sq. in. of sand-blasted iron wire, 17 3.81 3.20.

b. 0.78 sq. in. of polished copper wire, laminae. c. 0.87 sq. in. of polished aluminum wire, and 1 y!- amine 127-129 16.65 16.0 d. 0. 167 sq. 1n. of pollshed lead surface. 18 mm hylamino- Inhibitors for oil are rated on the bass of prevention ll-propyl 6 2 of oil deterioration as measured by the increase in acid 19 l l 0 I533 l -2 formation or neutralization number (NN) and kiney| 4-dimatic viscosity (KV) occasioned by the oxidation. The resultsofthe tests are rePorted in Table lamine 83-84 68.53 685310.54 10.52 13.32 13.7

20 l 1 -Dimethyl- 2-hydroxyethylamine (hydroxymethyl ethylamine The products of these examples were also tested in the catalystic oxidation test described previously. The same base fluid was used as before. The results are tabulated in Table IV.

prepared following the procedures of Example 2. In this series of examples, however, the mole ratio of amine to quinone was at least 1 to l. The operating times and temperatures and the reaction solvent were substantially the same. The analyses of the products prepared are tabulated in Table V.

TABLE V Carbon Hydrogen Crude melting point, calc'd found no. product 22 2-t-Butylamino- 1,4-naphthoquinone 3 ,3-Tetramethyl) butylamino- 1 ,4-naphthoquinone ethylamino)prop laminol ,4-naphthoquinone calcd found calcd found Nitrogen These products were tested in the catalytic oxidation test described previously. The same base fluid was used as before. The results are tabulated in Table VI.

The test was repeated at 450 F. (25 F. higher) with the following results (the headings are the same as above.)

None 8.3 585 13.7 22 2 3.86 1.74 Nil 3.0 24 0.5 9.38 210 Trace 1.0

Halogen and alkyl derivatives of the aminoquinones of this invention may be prepared by following the procedures of the previous examples.

EXAMPLE 28 a. In a suitable reactor is added 60 grams (0.82 mole) of .t-butylamine to a solution of 24.6 grams (0.1 mole) of chloranil in ml. of ethanol. The reaction proceeded exothermically. The desired product, 2,5- bis-t-butylarninodichloro-p-benzoquinone, was extracted with benzene and crystallized therefrom. The product was a red crystal; m.p. 163l 66 C.

Anal: Calcd for C I-I O N Cl %C, 52.68; %H, 6.31;

0 %N, 8.78; %Cl, 22.21

Found: %C, 52.57; %I-I, 6.48; %N, 9.06; %CI 21.65

b. Further crystallization yielded purple crystals of crude 2,5-bis-t-butylamino-3-chloro-p-benzoquin0ne; m.p. l10-112 C. Anal: Calcd for C I-I O N C1: %C, 59.05; %I-I, 7.44; %N, 9.84; %CI, 12.45

Found: %C, 56.16; %I-I, 7.63; %N, 8.89; %CI 13.86

EXAMPLE 29 a. Using the method of Example 1, oxygen gas was passed slowly into a stirred solution of 5 grams (0.03 mole) of 2-t-butylhydroquinone in 50 ml. of ethanol and 20 m1. of t-butyl-amine. After 6 hours of stirring the mixture, 2-t-butyl-5-t-butylamino-p-benzoquinone was obtained upon crystallization from benzene as red crystals; m.p. 9798 C.

Anal: Calcd for C 1-I ,O N: %C, 71.46; %H, 8.99; %N, 5.95

Found: %C, 68.06; %H, 8.75; %N, 5.80

b. This reaction was repeated using instead 10 grams (0.06 mole) of t-butylhydroquinone, 25 ml. of ethanol, and 10 grams (0.14 mole) of n-butylamine. The reaction was held for 4 hours. From the mixture was separated 2-t-butyl-5-n-butylamino-p-benzoquinone and 2-t-butyl-3,5-di-n-butylamino-p-benzoquinone.

(c) A third reaction, using 10 grams (0.06 mole) of tbutylhydroquinone, 30 ml. of ethanol, and 13 grams (0.12 mole) of benzylamine was conducted. Following the procedure of (a) above, the resulting mixture contained 2-t-butyl-5-benzylamino-p-benzoquinone and 2- t-butyl-3,5dibenzylamino-p-benzoquirione.

EXAMPLE 30 a. Following the procedure of Example 1, oxygen is passed slowly into a solution of grams (0.06 mole) of t-butylhydroquinone and 6.2 grams (0.62 mole) of n-hexylamine in 25 ml. of ethanol for 6 hours at room temperature. The gray-green crystals of 2-t-butyl3,5- di-n-hexylamino-p-benzoquinone (m.p. 174 C.) separated out.

b. The filtrate from (a) was evaporated oif leaving 2- t-butylm5-n-hexylamino-p-benzoquinone. These are reddish-purple crystals, crystallized from benzene; m.p. 56-58 C.

Anal: Calcd for C H O N: %C, 72.97; %H, 9.58; %N, 5.32

Found: %C, 71.29; %H, 9.35; %N, 5.22

EXAMPLE 31 a. Into a suitable reactor was added 8 grams of 2,5- bis-( 1 ,1-dimethyl-2-hydroxyethyl(amino )-pbenzoquinone (produced in accordance with the procedure of Example 2), 20 ml. of acetic acid and 12 grams of acetic anhydride were heated together at 130 C. for 3% hours. After distilling off acetic acid and unreacted acetic anhydride, red crystals of 2,5-bis-( l,1- dimethyl-2-acetoxyethylamino)-p-benzoquinone are obtained from ethanol crystallization; m.p. l63l65 C.

Anal: Calcd for C H O N %C, 59.00; %H, 7.15; %N, 7.65

Found: %C, 58.58; %H, 7.13; %N, 7.49

b. The caproyl derivative of (a) was produced by reacting 5 grams of the above aminoquinone with 4.9 grams of caproyl chloride in 25 ml. of dimethylforamide. The mixture is stirred for 2 hours and poured over crushed ice. The mixture is extracted with ether; removal of solvent yields crude 2,5-bis-( 1,1-dimethyl-2 -caproyloxyethylamino)-p-benzoquinone, a viscous red liquor.

Anal: Calcd for C H O N %C, 65.25, %H, 8.84; %N, 5.85.

Found: %C, 63.58; %H, 8.87; %N, 5.78

c. The 2,5-bis-(2-acetoxyethylamino)-p-benzoquinone was prepared by substantially the same method of Example 31 (a) from the 2-hydroxy-ethylamino intermediate.

EXAMPLE 32 Anal: Calcd for C H O N %C, 54.77; %H, 6.27; %N, 5.81 Found: %C, 54.54; %H, 6.37; %N, 5.86

b. The caproxyloxy derivative of (a) was obtained by reacting 8 grams of the amine with 13.8 grams of caproyl chloride in 25 ml. of dimethylformamide. The mixture is stirred for 1.5 hours and is poured over crushed ice. Ether is used to extract the product, which is freed of solvent by distillation. The resulting brown oil is 2,5-bis-( l, l -dicaproyloxymethylethylamino)-pbenzoquinone. Anal: Calcd for C i-1 0 m: %C, 64.56; %H, 8.84; %N, 3.96

Found: %C, 62.50; %H, 8.23; %N, 4.99

The products of Examples 28 to 32 were tested in the oxidation test described earlier, wherein the lubricant sample, using the same ester as the base fluid, is treated with air at 425 F. for 24 hours. The results of the test are tabulated in Table VII below:

The product of Example 30(b) was tested for oxidation inhibition in a solvent-refined mineral oil sample in the presence of the same metals as in the above described test. The test was conducted for 40 hours, at 325 F., in an air stream of 10 liters per hour. The oil was tested alone and in the presence of a boronated alkenyIsuccinimide ashless detergent, and in combinations of the aminoquinone and detergent. The results are tabulated in Table VIII.

TABLE VIII Increase Lead Conc. N.N. of KV at Loss,

Additive Wt.% Increase 2l0F. Sludge mg.

None 20.75 27l Medium Detergent 3.0 I904 367 Trace 262 EX. 30(b) l.0 0.58 l l Light 6 Detergent 3.0 0 8 Nil 4 Ex. 30(b) 1.0

EXAMPLES 3 3-39 Using procedures similar to those defined in Examples 1, 28 and 31, additional aminobenzoquinones were prepared. Table IX contains a tabulation of these compounds, together with the analytical results therefor. Example 33, Examples 34 and 35 and Examples 36-39, respectively, were prepared in accordances with Example 1, Example 28 and Example 31.

TABLE IX PHYSCAL CONSTANTS 2,5-Bis (4,4-dimethyl- S-hydroxypentylamino)- 1,4-benzoquinond42-145 65.47 65.5 2,5-Bisbenzylaminc-3,6-

dichloro oquinone225-227 61.65 62.0 2,5-Bismethyl- 2-hydroxyethylamdichloro- 1,4-benzoquinone 2,5-l3ismethyl- Z-butyrooxyethylamino) -l,4-benzoquinone 2,5-Bis- (1,l dimethyl-Z- benzoxyethylamino) -1,4-benzoquinnone 2,5-Bis- (4,4-dimethyl-S- pivaloxypentylamino)-1,4-

benzoquinone 132138 2,5-Bis- (1,1-dimethyl-2- pivaloxyethylamino)-1,4-

benzoquinone 142-145 62.8

The products of Table 1X were also tested in the catalytic oxidation test described hereinbefore, using the same base fluid. The results are given in Table X.

From the above tabulated data, it may be seen that the animoquinones of this invention are effective antioxidants under extremely adverse conditions.

Moreover they possess unexpected stability at high 5 temperatures. Many of these aminoquinones, particularly the tertiary-alkylaminoquinones, the acyloxy derivatives, and the halogen and alkyl derivatives, are novel compounds. They possess sufficient solubility in lubricating fluids to provide the required antioxidant stability. The compositions of this invention may be employed with additional additives present, namely detergents, dispersants, load carrying agents, anti-wear agents, viscosity index improvers, and the like.

Although this invention has been described with the aid of specific illustrations and working examples, the

scope of this invention is not limited thereto except as indicated in the following claims.

We claim:

the group consisting of RI! R and 1. An aminoquinone having a structure selected from five carbon caproyloxy and atoms;

pivaloxy;

l-methyl-4- (diethylamino)butyl; l,1-di(hydroxymethyl)ethyl; 2-

(3-diethylamino)propyl; and 2-(2-diethylamino)ethyl;

and R is selected from the group consisting of hydrogen, butyl and chloro, said R" occupying up to all of the available positions on the quinoid nucleus, and wherein only one of R and R may be hydrogen in any given aminoquinone.

2. The aminoquinone of claim 1 having the structure hydrogen.

5. The aminoquinone of claim 1, structure (2), wherein R is l,l-di(hydroxymethyl)ethyl and R is hydrogen.

6. The aminoquinone of claim 1, structure (2), 12. The aminoquinone of claim 1 having the strucwherein the amino groups are present at the 3,5-positure tions of the nucleus.

7. The aminoquinone of claim 1 wherein the quinone compound is selected from the group consisting of 2,5- 5 bis-t-butylamino-dichloro-pbenzoquinone, 2,5-bis-t- 1 butylamino-3-chloro-p-benzoquinone, 2,5-bisbenzylamino-3,6-dichloro-p-benzoquinone and 2,5- bis( 1 ,1-dimethyl-Z-hydroxyethylamino)-3 ,6-dichlorop-benzoquinone.

8. The aminoquinone of claim 1 having the structure H Ulla mm H o The aminoqulnone of claim 1 having the Structure 2O 13. The aminoquinone of claim 1 having the formula 10. The compound of claim 1 having the structure 14. The aminoquinone of claim I having the formula 11. The compound of claim 1 having the structure @omoem-o-ms- 

2. The aminoquinone of claim 1 having the structure
 3. The aminoquinone of claim 2 wherein R is 1,1-dimethyl-2-hydroxyethyl and R'' is hydrogen.
 4. The aminoquinone of claim 1, structure (2), wherein R is 1-methyl-4-(diethylamino)butyl and R'' is hydrogen.
 5. The aminoquinone of claim 1, structure (2), wherein R is 1,1-di(hydroxymethyl)ethyl and R'' is hydrogen.
 6. The aminoquinone of claim 1, structure (2), wherein the amino groups are present at the 3,5-positions of the nucleus.
 7. The aminoquinone of claim 1 wherein the quinone compound is selected from the group consisting of 2,5-bis-t-butylamino-dichloro-p-benzoquinone, 2,5-bis-t-butylamino-3-chloro-p-benzoquinone, 2,5-bis-benzylamino-3,6-dichloro-p-benzoquinone and 2,5-bis(1,1-dimethyl-2-hydroxyethylamino)-3,6-dichloro-p-benzoquinone.
 8. The aminoquinone of claim 1 having the structure
 9. The aminoquinone of claim 1 having the structure
 10. The compound of claim 1 having the structure
 11. The compound of claim 1 having the structure
 12. The aminoquinone of claim 1 having the structure
 13. The aminoquinone of claim 1 having the formula
 14. The aminoquinone of claim 1 having the formula 